Trouble in paradise? Vishnu/FFtec N54 335ii Single Turbo kits experiencing issues as a BimmerBoost member runs 12.5@121 with misfires and having to short shift

BimmerBoost would like to thank member GeorgiaTech335Coupe for his openness and honesty regarding his Vishnu/FFTEC single turbo setup. Recently, this member took his single turbo upgraded 6-speed manual 335i to the PBIR (Palm Beach International Raceway) dragstrip in Florida to do some testing. His best run was a 12.50@121.6 alongside a 12.8@117. Yes, these times are quite a ways away from the 10.8@131 glory pass from Vishnu demonstrating the kits capability.

This is in no way the fault of GeorgiaTech335Coupe who experienced misfires on his car and had to short shift at 6300 rpm in order to avoid them. Now, Vishnu has basically portrayed this kit as perfect and ready for sale with nobody having any issues. The reason BimmerBoost is bringing this issue to the attention of the community is for potential buyers to understand what they are getting into.

There is absolutely nothing wrong with having issues when modifying a car to this level and BimmerBoost is confident Vishnu will resolve them. There is something wrong with pretending nothing is wrong. A few cars with the single turbo kits have gone up for sale and apparently a total of three people, that are willing to open their mouths, are having misfire issues with these kits.

These issues will no doubt get resolved but potential buyers and current customers needs to be aware of the process, effort, and that progress is being made. Pretending nothing is wrong and collecting money simply is the wrong way to go about this and once again (it's becoming a trend) BimmerBoost is the only site bringing these issues to the attention of the community.

For the record, a member by the name of @tmo335tt says he has a hardware solution for the misfires that he will likely share with Vishnu (hopefully not for free). Interesting that it isn't Vishnu but the community solving this.

Thanks again to @GeorgiaTech335Coupe for sharing his details, good or bad, as we all learn thanks to honesty and openness. There is more to tuning than just collecting money.

2 gear changes in an MT adds significant time compared to the 1 shift usually done in a 6MT stock turbo car. That said, I'd be very surprised if he didn't have full boost well before or at 3800 RPM if he brake boosted the car and started it in the 45-50mph range. Shiv showed a video of his car making 1 bar around 3100ish RPM, which is what I would expect given the engine in question and the turbo used, so I'd be surprised if he really needed to start the car in 2nd for a good time.

yeah I probably need to brake-boost in 3rd to get any kind of respectable time.

That's what most people do but that's on stock turbos. Not sure if it'll get you in your powerband but it can only help. Brake boost around 45-50MPH, by the time you hit 60MPH hopefully you've hit full boost or close to it.

Originally Posted by GeorgiaTech335Coupe

yeah I probably need to brake-boost in 3rd to get any kind of respectable time.

VBOX has been proven to be very accurate. It's just a very accurate GPS that constantly records position and calculates speed/acceleration.

IHRA sanctioned track equipment still has to be placed correctly to work properly. They just use beams that are broken and record time between each beam break and calculate speed. Think of what would happen if those blocks were placed a couple feet short.

It's not that the Vbox isn't accurate. It just does not equal a slip like how some people treat it.

Whats interesting to me is that your 1/8th Mile trap speed is fairly stout - almost 97 mph. You are picking up just over 26 mph on the back half of the track. For comparison, i typically run 93 in the 1/8th, and trap 118, picking up 25mph on the back half. I would expect the ST to be a monster on the back half of the track, 1 mph difference seems like something is off.

Very good point, I also was picking up around 25MPH on the back half. I would think this is where the ST should shine.

Originally Posted by lulz_m3

Whats interesting to me is that your 1/8th Mile trap speed is fairly stout - almost 97 mph. You are picking up just over 26 mph on the back half of the track. For comparison, i typically run 93 in the 1/8th, and trap 118, picking up 25mph on the back half. I would expect the ST to be a monster on the back half of the track, 1 mph difference seems like something is off.

Whats interesting to me is that your 1/8th Mile trap speed is fairly stout - almost 97 mph. You are picking up just over 26 mph on the back half of the track. For comparison, i typically run 93 in the 1/8th, and trap 118, picking up 25mph on the back half. I would expect the ST to be a monster on the back half of the track, 1 mph difference seems like something is off.

Yes, exactly...and I'd bet money (enough to buy a new rear diff) that it's my gearing. At 125mph, I'm only at 5950rpm in 4th. If I shift 3rd at 7000rpm (~111mph), then 4th gear starts at 5280rpm.

You think 1st and 2nd gear are bad now though. Wait till you put that 3.46 in there. You're going to need real hoosier slicks and some dedicated lightweight drag wheels like some Koesi K1 17" or something.

You think 1st and 2nd gear are bad now though. Wait till you put that 3.46 in there. You're going to need real hoosier slicks and some dedicated lightweight drag wheels like some Koesi K1 17" or something.

Yeah I know. It's unfortunate but overall I think it'll be better. 1st is almost useless now anyway. I will be getting dedicated lightweight 17s and slicks eventually.

2 gear changes in an MT adds significant time compared to the 1 shift usually done in a 6MT stock turbo car. That said, I'd be very surprised if he didn't have full boost well before or at 3800 RPM if he brake boosted the car and started it in the 45-50mph range. Shiv showed a video of his car making 1 bar around 3100ish RPM, which is what I would expect given the engine in question and the turbo used, so I'd be surprised if he really needed to start the car in 2nd for a good time.

as i was reading your reply i was already contemplating brake boosting.

Originally Posted by GeorgiaTech335Coupe

Then I'd have to start in 2nd. That isn't good for 2 reasons: extra shift and 2nd gets very little traction.

shifting is what it is, but traction is easily attended to. i feel your pain on that, nothing you can do but get better tires. shouldnt be an issue with DR's though

Yeah I know. It's unfortunate but overall I think it'll be better. 1st is almost useless now anyway. I will be getting dedicated lightweight 17s and slicks eventually.

I am curious as to what you're current setup is? I already purchased some Kosei K1's and Hoosier DOT Drag Radials 275/40/17 if you want to wait to see how they perform on my car at the end of march (installing ST this weekend.)

Your timing in 4th explains the mediocre trap on the back end. Are you using NLS?

Yes for that particular run. If you look at the first datalog timing is where it is supposed to be in 4th (124.89mph trap).

That second log had 0 timing in 4th, not sure why. Maybe shifted too quickly.

I only used NLS for one run, but then turned it off becuase it almost always seems to make my timing flatline in 4th. That 2nd log was the only time 4th flatiline when not using NLS out of about 7 runs.

I am curious as to what you're current setup is? I already purchased some Kosei K1's and Hoosier DOT Drag Radials 275/40/17 if you want to wait to see how they perform on my car at the end of march (installing ST this weekend.)

I daily drive (and currently drag race) on 285/35-18s Nitto NT555R drag radials. The ones on my car now are very bald. I'm getting new ones in on Thursday so hopefully they offer more grip which I believe they will.

Yes for that particular run. If you look at the first datalog timing is where it is supposed to be in 4th (124.89mph trap).

That second log had 0 timing in 4th, not sure why. Maybe shifted too quickly.

I only used NLS for one run, but then turned it off becuase it almost always seems to make my timing flatline in 4th. That 2nd log was the only time 4th flatiline when not using NLS out of about 7 runs.